/usr/include/ is in libqca-qt5-2-dev 2.1.1-4+b2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/Qca-qt5/
/usr/include/Qca-qt5/QtCrypto/
/usr/include/Qca-qt5/QtCrypto/QtCrypto
/usr/include/Qca-qt5/QtCrypto/qca.h
/usr/include/Qca-qt5/QtCrypto/qca_basic.h
/usr/include/Qca-qt5/QtCrypto/qca_cert.h
/usr/include/Qca-qt5/QtCrypto/qca_core.h
/usr/include/Qca-qt5/QtCrypto/qca_export.h
/usr/include/Qca-qt5/QtCrypto/qca_keystore.h
/usr/include/Qca-qt5/QtCrypto/qca_publickey.h
/usr/include/Qca-qt5/QtCrypto/qca_safetimer.h
/usr/include/Qca-qt5/QtCrypto/qca_securelayer.h
/usr/include/Qca-qt5/QtCrypto/qca_securemessage.h
/usr/include/Qca-qt5/QtCrypto/qca_support.h
/usr/include/Qca-qt5/QtCrypto/qca_textfilter.h
/usr/include/Qca-qt5/QtCrypto/qca_tools.h
/usr/include/Qca-qt5/QtCrypto/qca_version.h
/usr/include/Qca-qt5/QtCrypto/qcaprovider.h
/usr/include/Qca-qt5/QtCrypto/qpipe.h